Pendent Triphenylamine Research Articles

Topological Design of Highly Anisotropic Aligned Hole Transporting Molecular Bottlebrushes for Solution-Processed OLEDs.

Polyvinyl polymers bearing pendant hole transport functionalities have been extensively explored for solution-processed hole transport layer (HTL) technologies, yet there are only rare examples of high anisotropic packing of the HT moieties of these polymers into substrate-parallel orientations within HTL films. For small molecules, substrate-parallel alignment of HT moieties is a well-established approach to improve overall device performance. To address the longstanding challenge of extension from vapor-deposited small molecules to solution-processable polymer systems, a fundamental chemistry tactic is reported here, involving the positioning of HT side chains within macromolecular frameworks by the construction of HT polymers having bottlebrush topologies. Applying state-of-the-art polymer synthetic techniques, various functional subunits, including triphenylamine (TPA) for hole transport and adhesion to the substrate, and perfluoro alkyl-substituted benzyloxy styrene for migration to the air interface, were organized with exquisite control over the composition and placement throughout the bottlebrush topology. Upon assembling the HT bottlebrush (HTB) polymers into monolayered HTL films on various substrates through spin-casting and thermal annealing, the backbones of HTBs were vertically aligned while the grafts with pendant TPAs were extended parallel to the substrate. The overall design realized high TPA π-stacking along the out-of-plane direction of the substrate in the HTLs, which doubled the efficiency of organic light-emitting diodes compared with linear poly(vinyl triphenylamine)s.

Synthesis of functional polyethylene via scandium catalysted copolymerization of ethylene with triphenylamine- or carbazole-substituted styrene derivatives

The copolymerization of ethylene with triphenylamine or carbazole substituted styrene derivatives was achieved to prepared functional polyethylene with pendant triphenylamine or carbazole groups using a rare earth metal catalyst (C5Me4SiMe3)Sc(CH2SiMe3)2(THF). The catalyst system showed high activity for the copolymerization of ethylene with triphenylamine or carbazole substituted styrene derivatives, affording copolymers with moderate molecular weight and narrow molecular weight distribution. In addition, the content of styrene derivatives in the copolymers can be adjusted by changing the feeding amount. Inspection of the aliphatic region of the 13C NMR spectrum reveal the random or pseudo-random sequence structure of the copolymers. Representative photophysical properties such as UV–vis absorption and fluorescence spectroscopy of the copolymers with different content have been characterized.

Electrochemical Characterization of Redox Probes Confined in 3D Conducting Polymer Networks.

In this manuscript we present a versatile platform for introducing functional redox species into tailor‐made 3D redox polymer networks. Electrochemical characterization based on cyclic voltammetry is applied to verify the immobilization of the redox species within the conducting networks. Ultimately this strategy shall be extended to (photo)electrocatalytic applications which will profit from the conducting polymer matrix. Soluble precursor copolymers are synthesized via radical copolymerization of vinyltriphenylamine (VTPA) with chloromethylstyrene (CMS) in different ratios, whereas CMS is subsequently converted into azidomethylstyrene (AMS) to yield poly(VTPA‐co‐AMS) copolymers. Spin‐coating of poly(VTPA‐co‐AMS) on gold electrodes yields thin films which are converted into stable polymer network structures by electrochemical crosslinking of the polymer chains via their pendant triphenylamine groups to yield N,N,N′,N′‐tetraphenylbenzidine (TPB) crosslinking points. Finally, the resulting redox‐active, TPB‐crosslinked films are functionalized with ethynylferrocene (EFc) as a representative redox probe using a click reaction. Main experimental tools are polarization modulation infrared reflection absorption spectroscopy and scan rate dependent cyclic voltammetry. Especially the latter proves the successful conversion and the immobilization of redox probes in the polymer matrix. The results are compared with the reference system of azide‐terminated self‐assembled monolayers on gold substrates, allowing to distinguish between free and immobilized EFc species.

Binary/ternary memory behavior of organo-solubility polyimides containing flexible imide linkages and pendent triphenylamine or 3, 4, 5-trifluobenzene moieties

Two different aromatic diamines monomers (3, 5-diamino-N-(4'-phenyl-4''-triphenylamino)-N-(4''-benzyl-4'''-triphenylamino)benzamide (DPTBTB) and 3, 5-diamino-N-(4'-3'', 4'', 5''-trifluorobiphenyl)-N-(4''-benzyl-3''', 4''', 5'''-trifluorophenyl)benzamide (DTBTB)) containing flexible linkages were designed and synthesized, respectively. Four organo-solubility polyimides (PI-a, PI-b, PI-c, and PI-d) were prepared via a two-step procedure with pyromellitic dianhydride (PMDA) and 3, 3', 4, 4'-biphenyltetracarboxylic dianhydride (BPDA), respectively. The four PIs performed excellent thermal stability with the temperature of 5% weight loss in range of 370–420 ℃ at N2 atmosphere. The Al/PI-a/ITO and Al/PI-b/ITO memory devices exhibited binary write-once-many-read (WORM) and rewritable (Flash) behavior, respectively. But the Al/PI-c/ITO and Al/PI-d/ITO memory devices showed ternary WORM and Flash behavior due to the deeper charge traps came from the fluorinated groups in the structure of PI-c and PI-d, respectively. The memory switching mechanism could be demonstrated through molecular simulation. The results gave an effective strategy that adjusting the structure of PI to achieve different memory effects.

Synthesis of asymmetrically substituted head‐to‐head polyacetylenes from 2,3‐disubstituted‐1,3‐butadienes

ABSTRACTAsymmetrically substituted head‐to‐head polyacetylenes with phenyl and triphenylamine, thienyl or pyrenyl side groups were synthesized through anionic or controlled radical polymerization of 2,3‐disubstituted‐1,3‐butadienes and subsequent dehydrogenation process. Anionic polymerizations of the designed monomers bearing pendent triphenylamine and thienyl group gave narrow disperse disubstituted precursor polybutadienes with exclusive 1,4‐ or 4,1‐structure, which were confirmed by GPC and NMR measurements. In addition, the monomers possessing pyrenyl group were polymerized via nitroxide mediated radical polymerization and the resulting polymers were obtained with controlled molecular weight and low polydispersities. These polybutadiene precursors were then dehydrogenated in the presence of 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone. Thus asymmetrically substituted head‐to‐head polyacetylenes were obtained as indicated by 1H NMR. The properties of polybutadiene precursors and the corresponding polyacetylenes were analyzed by UV–vis, DSC, and TGA. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 395–402

Nonvolatile write‐once read‐many‐times memory behaviors of polyimides containing tetraphenyl fluorene core and the pendant triphenylamine or carbazole moieties

ABSTRACTTo better understand the structure–property relationships, two novel aromatic diamines containing tetraphenyl fluorene (TPF) moiety through triphenylamine (TPA) unit and carbazole (Cz) unit modification are designed and synthesized, respectively. Four thermally stable and excellent solubility polyimides are prepared and characterized. The excellent film‐formation ability and thin film stability are investigated by X‐ray diffraction (XRD) and atom force microscopy (AFM) measurements, respectively. The memory devices are fabricated, PIs films with low water uptakes sandwiched between indium‐tin oxide (ITO) ground electrode and Al top electrode, and exhibit nonvolatile write‐once read‐many‐times (WORM) memory behaviors with low threshold voltages, due to increasing the retention time through regulating the energy level. The current conduction mechanisms of all devices are linearly fitted by theoretical conduction model. Molecular simulations are used to demonstrate switching mechanism and the memory effects. The experimental results provide a sight for the design‐adjustable switching voltage of memory devices. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1630–1644

Ternary memory property of novel polyimide with backbone carbazole moiety and pendant triphenylamine moiety

The polyimide (TPA-Cz PI) was synthesized by the reaction of 9-(4′-(4′-diphenylamino)phenylbenzyl)-3,6-diaminocarbazole with 2,2′,3,3′-biphenyltetracarboxylic dianhydride through a classical two-step polymerization process. It exhibited excellent organo-solubility and self-extinguishing property. The synthesized TPA-Cz PI shown excellent film formation. The TPA-Cz PI film sandwiched between an indium tin oxide bottom electrode and Al top electrode. And the fabricated memory device exhibited ternary rewritable storage property in the bias with good data retention and the current ratio of 104:102:1 for ON2, ON1, and OFF states. Its current conduction mechanism by the I-V curves of different conduction models based on the experimental data was analyzed and used to illuminate the physical nature of resistance switching effects. The experimental result indicates that field-induced conformational ordering of the TPA-Cz PI chains and charge-transfer interaction between electron-donor and electron-withdrawing are responsible for the switching behavior. This work can provide a sketch for the design and selection of ternary state resistance random access memory materials in future research.

Synthesis of Fluorescent Micro- and Mesoporous Polyaminals for Detection of Toxic Pesticides

This paper presents the first report on employing fluorescent porous organic polymers as sensors for the detection of toxic pesticides. Specifically, fluorescent micro- and mesoporous polyaminals with pendant triphenylamine and dibromotriphenylamine chromophore groups are synthesized, which exhibit BET surface area up to 507 m2 g–1, adjustable pore sizes in the range from 0.5 to 36.2 nm and can emit bright turquoise light under the ultraviolet lamp. Using the insecticide (fenitrothion) and herbicides (trifluralin and glyphosate) as analytes, the chemosensing properties are investigated by correlating the porosity parameters and chemical structure of the polymers with the molecular sizes and the energy in the lowest unoccupied molecular orbital of pesticides. Moreover, the effects of different acid–base conditions and solvents including ethanol, water, chloroform, tetrahydrofuran, and N,N-dimethylformamide on the chemosensing sensitivity of the polymers are also studied in detail. Particularly, the chemose...

Chiral Selective Dispersion of Arc-Discharged Single-Walled Carbon Nanotubes by Aromatic Polyimides with Pendent Triphenylamine Units

Chiral Selective Dispersion of Arc-Discharged Single-Walled Carbon Nanotubes by Aromatic Polyimides with Pendent Triphenylamine Units

New high-solubility aromatic polyesters with pendent phenothiazine: Synthesis, electrochromic and optoelectronic properties

A series of aromatic polyesters were synthesized from dicarboxylic acids, containing pendent triphenylamine substituted with phenothiazine, and five different kinds of bisphenols. The aromatic polyesters exhibited good solubility in organic solvents due to bulky propeller-like triphenylamine and butterfly-like conformation of phenothiazine, which were convenient for the polymers to fabricate films and devices by spin- or inject-coating. They also revealed good thermal stability with 10% weight lost at 420°C. In addition, the polymer showed a strong yellow fluorescence at 522nm in the THF solution and irregular solvatochromic characteristic in polar solvents. Furthermore, their films had well reversible redox process in the range of 0–1.2V with the color changing from colorless neutral to red in the range of 0.80–0.85V. The calculated HOMO and LUMO energy levels of polyesters demonstrated their potential application as photoelectrical materials.

Ambipolar and multi-electrochromic polyimides based onN,N-di(4-aminophenyl)-N′,N′-diphenyl-4,4′-oxydianiline

A series of novel aromatic polyimides were synthesized from N,N-di(4-aminophenyl)-N′,N′-diphenyl-4,4′-oxydianiline and aromatic tetracarboxylic dianhydrides through a conventional two-step procedure. Most of the polyimides exhibited reasonable solubility in organic solvents and could afford robust films via solution casting. The polyimides exhibited high thermal stability, with glass transition temperatures in the range 227–273 °C and 10% weight-loss temperatures in excess of 550 °C. All the polyimide films showed ambipolar redox and multi-electrochromic behaviors. They exhibited two reversible oxidation redox couples at 0.94–0.98 and 1.09–1.12 V versus Ag/AgCl in acetonitrile solution. A coupling reaction between the radical cations of the pendent triphenylamine units occurred during the oxidative process forming a tetraphenylbenzidine structure which resulted in an additional redox state and color change. © 2014 Society of Chemical Industry

Facile anionic synthesis of well-defined block copolymers with pendent triphenylamine and ethynylpyridine for nonvolatile memory device applications with high performances

The sequential block copolymerization of 4,4′-vinylphenyl-N,N-bis(4-tert-butylphenyl)benzenamine (A) with 2-(2-(4-vinylphenyl)ethynyl)pyridine (B) was simply carried out using only potassium naphthalenide (K-Naph) as an initiator without any additives in tetrahydrofuran (THF) at −78 °C. The well-defined functional block copolymers containing A block as an electron donor and B block as a weak electron acceptor had predictable molecular weights (Mn = 8,800–14,500 g/mol) and narrow molecular weight distributions (Mw/Mn = 1.09–1.10). The bicontinuous microphase-separated film morphology of the precisely synthesized poly(B-b-A-b-B) (PBAB) with 0.71 of fpoly(A), formed by thermal annealing at 230 °C for 9 h, was expected to be a potential active layer for nonvolatile memory device applications. Indium tin oxide (ITO)/PBAB/aluminum (Al) memory devices with an 8 × 8 cross-bar array structure exhibited nonvolatile resistive switching characteristics. The memory devices showed reliable memory performance in terms of ON/OFF ratios of ∼104, endurance cycles and retention time, and statistical data with regard to cumulative probability of the switching currents and threshold voltage distribution. Filamentary conduction mechanism was proposed to explain the switching of PBAB-based memory devices. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2625-2632

Synthesis and Electrochromic Properties of Aromatic Polyamides with Pendent Triphenylamine Units

Three series of electroactive polyamides are prepared, from 4‐(3,5‐diaminobenzamido)triphenylamine (4), 4‐(3,5‐diaminobenzamido)‐4′,4″‐di‐tert‐butyltriphenylamine (t‐Bu‐4), and 4‐(3,5‐diaminobenzamido)‐4′,4″‐dimethoxytriphenylamine (MeO‐4), respectively, with aromatic dicarboxylic acids via phosphorylation polyamidation reactions. The resulting polyamides are easily soluble in polar organic solvents and can be solution‐cast into flexible and strong films. They exhibit high thermal stability with glass transition temperatures (Tg) in the range of 264–306 °C and 10% weight‐loss temperatures in excess of 470 °C. The polyamides derived from diamines t‐Bu‐4 and MeO‐4 exhibit reversible electrochemical oxidation, accompanied by strong color changes with high contrast ratio and electrochromic stability. The remarkable electrochromic behavior of the polymer film is clearly interpreted on the basis of spectro‐electrochemical studies. For the polyamides derived from diamine 4, the triphenylamine radical cations formed during the oxidative process will dimerize to a tetraphenylbenzidine structure, leading to an additional oxidation state and color change. image

Synthesis and electrochromic properties of aromatic polyimides bearing pendent triphenylamine units

A series of aromatic polyimides with pendent triphenylamine group were synthesized from equimolar mixtures of 4,4′-oxydianiline (ODA) and 4-(3,5-diaminobenzamido)triphenylamine (4), 4-(3,5-diaminobenzamido)-4′,4″-di-tert-butyltriphenylamine (t-Bu-4) or 4-(3,5-diaminobenzamido)-4′,4″-dimethoxytriphenylamine (MeO-4) with two aromatic tetracarboxylic dianhydrides (DSDA or 6FDA) via a conventional two-step procedure that included a ring-opening polyaddition to give poly(amic acid)s, followed by chemical imidization. These polyimides exhibited good solubility in polar organic solvents and could be solution-cast into flexible and strong films. They showed excellent thermal stability, with Tg values in the range of 284–309 °C. The polyimides derived from diamines t-Bu-4 and MeO-4 exhibited reversible electrochemical oxidation, accompanied by strong color changes with high contrast ratio and electrochromic stability. For the polyimides derived from diamine 4, the coupling reaction between the triphenylamine radical cations occurred during the oxidative process forming a tetraphenylbenzidine structure, which resulted in an additional oxidation state and color change together with enhanced near-IR absorption at fully oxidized state.

Synthesis and photovoltaic properties of fluorene-based copolymers with pendent donor–acceptor units

Two fluorene-based copolymers comprising identical pendent triphenylamine (donor)–benzothiadiazole (acceptor) unit on the C9 site of fluorene but different conjugated main chain structures were synthesized by Pd-catalyzed Stille reaction. The thermal, photophysical, electrochemical and photovoltaic properties are studied. The polymers have strong absorption in 300–650 nm. The bulk heterojunction solar cells were fabricated with the copolymers as the donors and PC71BM as the acceptor in a 1:3 weight ratio in the device configuration ITO/PEODT/copolymer:PC71BM (1:3)/LiF/Al. The power conversion efficiency of the device based on copolymer PF-BTh-DTS is 1.1 % with open-circuit voltage (V oc) 0.84 V under simulated AM 1.5 G solar irradiation (100 mW/cm2).

Synthetic pathway to functional block copolymers with pendent triphenylamine and ethynylpyridine: Effect of countercation on anionic polymerization behavior

The block copolymerization of 4,4′-vinylphenyl-N,N-bis(4-tert-butylphenyl)benzenamine (A) with 2-(2-(4-vinylphenyl)ethynyl)pyridine (B) was performed using sec-butyllithium (s-BuLi) as an initiator in the absence and presence of potassium tert-butoxide (KOBut) in tetrahydrofuran (THF) at −78 °C. The block copolymerization was not successful in the absence of KOBut, whereas the well-defined diblock copolymer (poly(A-b-B)) containing pendent triphenylamine and ethynylpyridine was successfully synthesized in the presence of excess KOBut due to the change in the countercation from Li+ to K+ and the suppression of ion dissociation by the salt common effect. The poly(A-b-B)s had predictable molecular weights (Mn = 4,900–20,000 g/mol) and narrow molecular weight distributions (Mw/Mn = 1.13–1.15). In addition, the resulting block copolymer showed good solubility and excellent thermal properties. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4233–4239

Novel aromatic polyimides with pendent triphenylamine units: Synthesis, photophysical, electrochromic properties

A new triphenylamine-containing aromatic diamine, N-(4-triphenylamine-phenyl)-3,5-diaminobenzamide, was synthesized from 4-aminotriphenylamine and 3,5-dinitrobenzoyl chloride. A series of novel aromatic polyimides with pendent triphenylamine units were prepared from the newly synthesized diamine and various aromatic tetracaboxylic acid dianhydrides via polycondensation. These polyimides have inherent viscosities of 0.36–0.47dl/g. They are readily soluble in many organic solvents, such as NMP, DMAC, DMF and DMSO. They can be solution-cast into transparent, tough, and brittle films with good mechanical properties. These aromatic polyimides display outstanding thermal stabilities, i.e. 10% weight-loss temperatures in excess of 540°C under nitrogen. Cyclic voltammograms of the polyimide films on an indium-tin oxide (ITO)-coated glass substrate exhibit one pair of reversible redox couple at half-wave oxidation potentials (E1/2) around 0.82–0.850V, respectively, versus Ag/AgCl in acetonitrile solution. The electrochromic properties were examined by spectroelectrochemical methods. All the polymer films reveal good electrochemical and electrochromic stability by repeatedly switching electrode voltages, with coloration change from the green neutral state to the red or blue oxidized state.

New Donor−Acceptor Random Copolymers with Pendent Triphenylamine and 1,3,4-Oxadiazole for High-Performance Memory Device Applications

We report the synthesis and resistive-type switching memory characteristics based on new P(VTPAxBOXDy) and P(CNVTPAxBOXDy) random copolymers containing different donor/acceptor ratios (8/2, 5/5, and 2/8) of pendent electron-donating 4-vinyltriphenylamine (VTPA) or 4,4′-dicyano-4′′-vinyltriphenylamine (CNVTPA) and electron-withdrawing 2-(4-vinylbiphenyl)-5-(4-phenyl)-1,3,4-oxadiazole (BOXD). The effects of donor/acceptor ratios and cyano side group on the memory characteristics were explored and compared with properties of homopolymers, PVTPA, PCNVTPA, and POXD. The distinct electrical current−voltage (I−V) characteristics of the ITO/P(VTPAxBOXDy)/Al device changed from volatile memory to insulator depending on the relative donor/acceptor ratios. The ITO/P(VTPA8BOXD2) or PVTPA/Al device exhibited SRAM or DRAM behavior with an ON/OFF current ratio of 107−108. However, no switching phenomena were observed for a higher BOXD ratio. Moreover, the devices could endure 108 cycles under a voltage pulse and show a ...

Electrocoupling process and electrochemical deposition of poly(9-vinylcarbazole-co-4-vinyltriphenylamine) films

Poly(9-vinylcarbazole-co-4-vinyltriphenylamine)s, PVKT21 and PVKT45 with 21 mol% and 45 mol% pendant triphenylamine groups respectively, were electrochemically deposited as crosslinked thin films through electrocoupling of pendant triphenylamine moieties during the oxidation process. The electrocoupling process has been elucidated by electrochemical and spectroelectrochemical investigations which reveal that mainly triphenylamine undergoes electrocoupling. The color of the electrodeposited film changes from colorless (neutral state) to orange (semi-oxidized state) and finally to bluish-green (fully oxidized state) when the applied potential is increased from 0 V to 2 V. Electrodeposited films were characterized by atomic force microscope (AFM) and the results show that their morphology can be controlled by changing the precursor concentrations. Through this method a smooth thin film can be fabricated for the application in electroluminescent devices. The electroluminescent devices using electrodeposited PVKTs as hole-transporting layer effectively enhance device performance.

Novel extended π-conjugated Zn(II)-porphyrin derivatives bearing pendant triphenylamine moiety for dye-sensitized solar cell: synthesis and characterization

We have designed and synthesized novel Zn(II) -porphyrin derivatives for dye-sensitized solar cells. The derivatives incorporate the electron-donating group of a pendant triphenylamine into cyano-substituted ( [TPA]Zn-Por-CN1 ) or non-substituted stilbene moiety ( [TPA]Zn-Por1 ) in the 5,10,15-meso-position and carboxylic acid group in the 20-meso-position in a porphyrin derivative. Their chemical structures were characterized by 1H NMR, FT-IR, UV-vis absorption, EI-mass, and MALDI-TOF mass spectroscopies. Their electrochemical properties were studied by cyclic voltammetry measurement. These Zn(II) -porphyrin derivatives have been used to fabricate dye-sensitized solar cells based on I-/I2 liquid electrolytes as dye sensitizers and their device performances were evaluated by comparing with that of a standard Ru(II) complex dye. [TPA]Zn-Por-CN1 showed higher power conversion efficiency than that of [TPA]Zn-Por1 , due to a broader absorption band around 435 nm. Short-circuit photocurrent density (Jsc), open-circuit voltage (Voc), fill factor (FF), and power conversion efficiency (η) of DSSC for [TPA]Zn-Por-CN1 were evaluated to be Jsc = 6.3 mA.cm-2 , Voc = 0.737 V , FF = 0.683 , and η = 3.1% , respectively.